Fake.Core.Context 5.20.0-alpha.1580

(Minor) BREAKING: Drop support for `net462` and update to `net472`. ENHANCEMENT: Keep unreleased changelog section when promote to new version, thanks @vilinski - https://github.com/fsharp/FAKE/pull/2480 ENHANCEMENT: Added SignTool for v5, thanks @jhromadik - https://github.com/fsharp/FAKE/pull/2444 ENHANCEMENT: Remove old netstandard1.6 dependencies, thanks @teo-tsirpanis - https://github.com/fsharp/FAKE/pull/2493 ENHANCEMENT: Add support for running Octo as dotnet tool, thanks @jeremyabbott - https://github.com/fsharp/FAKE/pull/2489 ENHANCEMENT: Add support for `--include-symbols` in `dotnet pack`, thanks @devployment - https://github.com/fsharp/FAKE/pull/2508 ENHANCEMENT: Add support for default proxy credentials to GitHub (Octokit), thanks @csmager - https://github.com/fsharp/FAKE/pull/2507 ENHANCEMENT: `Fake.DotNet.FSFormatting` supports the 4.0 RC release BUGFIX: Update FCS, fixes ionide FAKE support (https://github.com/fsharp/FsAutoComplete/issues/561), thanks @baronfel - https://github.com/fsharp/FAKE/pull/2475, https://github.com/fsharp/FAKE/pull/2479, https://github.com/fsharp/FAKE/pull/2481, https://github.com/fsharp/FAKE/pull/2500 BUGFIX: Fix Paket.restore references-files, thanks @nilshelmig - https://github.com/fsharp/FAKE/pull/2474 BUGFIX: Fix/octo args to string bug, thanks @ids-pfinn - https://github.com/fsharp/FAKE/pull/2469 BUGFIX: Fix an AppVeyor environment variable (`APPVEYOR_REPO_COMMIT_MESSAGE_EXTENDED`) returning `null`, thanks @teo-tsirpanis - https://github.com/fsharp/FAKE/pull/2448 BUGFIX: Fix potential `FileNotFoundException` when cache is outdated. DOCS: Fixed typos and improved docs, thanks @milbrandt, @jzabroski, @objectx - https://github.com/fsharp/FAKE/pull/2492, https://github.com/fsharp/FAKE/pull/2497, https://github.com/fsharp/FAKE/pull/2502